Electromagnetic relay.



A. P. YOUNG & A. H. ST. C. WATSON.

ELECTROMAGNETIC RELAY.

APPLICATION FILED MAYZI. 1915.

1,1 90,066. Patented July 4, 1916.

'inx/entors: Arthur PYoung.

Alex anderHStCWaLson TheirAttorneg.

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UNITED STATES PATENT OFFICE.

ARTHUR I. YOUNG, OF KENILJVORTI-I, AND ALEXANDER H. ST. 0. WATSON, OFCOVEN- TRY, ENGLAND, ASSIG'NORS TO GENERAL ELECTRIC COMIANY, ACORPORATION OF NEW YORK.

Application filed May 21, 1915.

b all whom it may concern Be it known that we, Arcrnnn P. YOUNG, asubject of the King of Great Britain, residing at Dovetail, Priory Road,Kenilworth, in the county 01 Vvarwick, England, and rriinmnnnn H. ST. C.\VA'rsoN, a subject of the King of Great Britain, residing at Farlsdon,Coventry, in the county of Varwiek, England, have invented certain newand useful Improvements in Electromagnetic Relays, of which thefollowing is a specification.

Thisinvention relates to electromagnetic relays, and has for its objectto produce a relay of simple construction in which a plu *ality ofmovable armaturcs may be simultaneously actuated from a single coil andin which a strong pull may be obtained with the minimum voltage on whichit is desired to operate the same.

Electromagnetic relays are provided for various purposes, and inparticular for use with voltage regulators of the Tirrill type. In thepatent to Tirrill, #1,101,670, there is shown a type of relay wherein aplurality of cores and associated movable armatures may be magnetizedfrom a pair of coils. In this patent the cores are E-shaped and themagnetic pull is distributed along the length of the armature arm. v

Our invention has particular relation to an improved relay of this typeand its construction will be more readily understood by reference to theaccompanying drawing, in which:

Figure 1 is a diagrammatic view illustrating the connections of therelay when used in conjunction with a Tirrill regulator; Fig. 2 is aplan view of a fragment of a coil of such a. relay provided wit-h twocores; and Fig. 3 is a cross-section on the line 33 of Fig. 2.

e shall first describe the operation of a relay of this type inconnection with a Tirrill regulator operating upon the field of anexciter, and then describe the particular construction which constitutesour invention. An alternating current generator 10 is pro vided with afield winding 11 which is excited from the exciter 12; this exciter inturn being provided with a field winding 13 in series with which is aresistance 14. The regulator illustrated is provided with movablecontact arms 20 and 21', the arm 20 Specification of Letters Patent.

Patented July 4, 1916.

Serial No. 29,691.

moving in response to the varying strengths of the coil 22 energized inproportion to the cXciter voltage, while the arm 21 moves in response tothe varying strengths of the coil 23 energized in proportion to thealternating current generator voltage. The relay 30 is then arrangedwith its contacts 31 shortcircuiting the resistance 14, the usualcondenser 15 being shunted across the said contacts to minimize thesparking. This relay is greterably wound differentially, one windingbeing permanently connected with the exciter brushes, while the winding33, arranged in opposition thereto, is so connected that it will beenergized when the contacts carried on the arms 20 and 21 close. Asuitable resistance 31 is provided to reduce the How of current in thewindings oi the relay.

The windings 32 and 33 are preferably wound non-inductively in a singlecoil having a considerable internal diameter and a relatively smallcross-section. Surrounding one side of this coil are a plurality ofmagnetic cores 35, forming a substantially closed rectangle, the ends 36of which project outwardly so that the magnetic circuit is incomplete. Amovable armature 37 is then arranged to be attracted by the outwardlyprojecting ends 36 of the core. This armature is preferably made in theform of a bell crank lever pivoted to the supporting frame-work 10, andprovided with a spring 38 arranged to hold the armature away from theprojecting ends 36 and to close the contacts 31. A fixed contact may besupported in any convenient manner, as upon a post 39. The partsdescribed are preferably arranged in the manner illustrated in thedrawing, so that the coil has its diameter substantially parallel to thesupporting base 10. The cores 35 are then placed so that theirprojecting ends 36 are away from the supporting base upon which themovable armature 37 is pivoted. In operation, it will be seen that,whenever the contacts upon the movable arms 20 and 21 of the regulatorare separated so that the winding 33 is deenergized, the winding willbecome effective, and the movable armature 37 will be attracted to openthe contacts 31. resistance 1% in the exciter field and thereby producethe desired regulation in a well understood manner. i

This will result in inserting the Although we have herein described ourdevice in its particular application to use with a voltage regulator, itwill be understood that it is in no wise limited to such a use, and isapplicable to any case where it is desired to attract a plurality ofmovable armatures simultaneously. By means 031. the particular sha e ofthe magnetic core used in our invention, it will be seen that We areenabled to dispense with one of the coils of the relay illustrated inthe patent to 'lirrill a sore mentioned, and that, in addition, .TQ haveconcentrated the flux ata point removed from the pivot of the movablearmature and thereby increased the ell'ectire turning moment. Thiscombination results in not only simplifying the construction, but alsoin increasing the pull obtained with the minimum voltage at which itdesired to operate. Since in the particular application herein describedthe e. citer voltage varies over a considerable range, it will be seenthat this feature be comes particular 5* important, since it enables usto design the spring 38 with considerably greater strength thanformerly. This results in increasing the speed with which the relayoperates to close the contacts 31 when both windings of the coil areenergized.

While u'e hare herein shown and described one particular form (it ourinvention, WC wish it understood that we are not limited thereto andthat our invention, while extending to all the details of construction,is only limited by the scope of the appended claim.

ll hat We claim as no and desire to secure by Letters Patent of theUnited States, is,

in electromagnetic rela} comprising a dilterentially Wound coi'i ofsubstantial internal diameter, a plurality of magnetic coressubstantially sin-rounding one side of said coil to form an incompletemagnetic circuit having, two projecting closely adjacent ends, a movablearmature for each core pivotalljv mounted at a point remote from saidends and adapted to close said magnetic circnit when attracted by saidcore, said armature carrying a contact, and a lined contact ceoperatinstherewith.

In r-iitness whereof, we hare hereunto set our hands this 4th day ofMay, 1M5.

ARTHUR P. YOUNG. ALEXANDER ll. ST. C. iVitTSON.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patentsv Washington, 1). G.

